Context: 262144 was measured before it was deployed -- 24.72 GB on GPU 0 and 29.14 GB on GPU 1 of 34.21 GB each, ~5 GB of headroom on the busier card, and a 140,069-token prompt prefilled through the single slot in 134 s to prove the window is real. The 114688 wall was the vLLM predecessor's arithmetic, not this runtime's. Throughput, measured through the service: 1.0-1.4k tok/s prefill from 4k to 140k, 43.8 tok/s decode on a 512-token generation, 41-71 % DFlash2 acceptance, and the prefix cache re-prefilling 4 of 998 tokens on a repeated prompt. The signals move with the runtime, so the fleet's rules and dashboard are re-cut rather than renamed: vllm: series do not exist any more, and two of the old rules watched things llama.cpp does not export at all (KV-pool fill, p95 latency). Those are retired with the reason written down, and LlmSpecDecodeOff takes one of the slots -- a lost drafter is the failure no client can see. The observability seam now fails if any rule names a series the endpoint does not export, which is what would have caught the stale vllm: expressions. omp models.yml (outside the repo) is updated in the same pass: contextWindow 262144, and the full reasoning-effort map, because Qwen3.8's template answers 500 on 'high' -- verified against the live endpoint, low/medium/xhigh answer 200. Subagents run at high.
99 lines
4.7 KiB
YAML
99 lines
4.7 KiB
YAML
# Alerting and recording rules for the LLM fleet.
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#
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# Every expression here is keyed to a series that EXISTS as of 2026-09-16. When
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# frank-medium moved from vllm-radiance to llama.cpp the exported namespace
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# changed with it (vllm: -> llamacpp:), and two signals the old file alerted on
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# no longer exist in any form:
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#
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# * vllm:kv_cache_usage_perc — llama.cpp exports no KV-fill gauge. Its
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# observable consequence is queueing, which is what LlmRequestsQueueing
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# watches instead. A renamed query would have been a rule that can never
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# fire.
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# * vllm:e2e_request_latency_seconds_* — no latency histogram either. The
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# rule it fed (p95 wall clock) is retired rather than restated, and
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# LlmSpecDecodeOff takes its place: the failure an operator actually
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# cannot see from the outside on this deployment.
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#
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# IMPORTANT: nothing is notified. There is no Alertmanager in this stack, so a
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# firing alert appears on Prometheus' /alerts page, in the ALERTS metric (which
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# the LLM fleet dashboard graphs) and nowhere else. Turning these into something
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# that reaches a person means adding an Alertmanager or using Grafana's own
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# alerting with a contact point — a decision about how Frank wants to be paged,
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# not a missing line of configuration.
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groups:
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- name: llm-fleet
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interval: 30s
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rules:
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# Recording rule so the dashboard and the alert below share one
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# expression. The exported series are counters; the rate is the reuse.
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- record: job:llm_prefix_cache_reuse:rate5m
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expr: |
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rate(llamacpp:prompt_tokens_cached_total[5m])
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/ clamp_min(rate(llamacpp:prompt_tokens_total[5m]), 0.001)
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# The capacity wall, in the only form llama.cpp exports it: work waiting
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# for the single slot. Past here the next large request queues.
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- alert: LlmRequestsQueueing
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expr: llamacpp:requests_deferred > 0
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for: 10m
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labels:
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severity: warning
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annotations:
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summary: "{{ $labels.job }}: requests waiting for 10 minutes"
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description: >-
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The endpoint's slot(s) are busy and work is queueing. Either the
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fleet is genuinely busy or one endpoint is carrying it alone. With
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--parallel 1 a second concurrent request always shows up here.
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# The thrash signature measured on 2026-09-16: requests keep arriving but
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# almost none are served from cache, which is what several concurrent
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# 50-80k-token conversations do to this fleet.
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- alert: LlmPrefixCacheCollapse
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expr: >-
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job:llm_prefix_cache_reuse:rate5m < 0.20
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and rate(llamacpp:prompt_tokens_total[5m]) > 0.05
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for: 15m
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labels:
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severity: info
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annotations:
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summary: "{{ $labels.job }}: prefix reuse below 20 % for 15 minutes"
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description: >-
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Nearly every request is prefilling from scratch. If several large
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contexts are in flight together, this is the capacity wall rather
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than a routing fault.
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# The speculative path is the one failure no client can see: the server
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# answers normally, just at half the speed, when the drafter is gone.
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# Drafts and accepts are counters, so a rate that stays at zero while the
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# endpoint is serving tokens means nothing is being drafted.
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- alert: LlmSpecDecodeOff
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expr: >-
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rate(llamacpp:spec_decode_num_drafts_total[5m]) == 0
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and rate(llamacpp:tokens_predicted_total[5m]) > 0.1
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for: 15m
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labels:
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severity: warning
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annotations:
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summary: "{{ $labels.job }}: serving without speculative decoding"
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description: >-
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Tokens are being produced but no draft has been proposed for 15
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minutes. On frank-medium that means the DFlash2 drafter is not
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running (check the unit's log for common_speculative_impl_draft_dflash),
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and the endpoint is decoding autoregressively.
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# The endpoint, not a replica: one process serves each port now, so a
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# restart of the unit is a scrape gap, not a failover.
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- alert: LlmEndpointDown
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expr: up{job=~"frank-.*"} == 0
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for: 2m
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labels:
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severity: critical
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annotations:
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summary: "{{ $labels.job }}: scrape target down for 2 minutes"
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description: >-
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Prometheus cannot reach the LLM endpoint. Check the units:
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`systemctl is-active frank-medium` on Dankserver (a root llama.cpp
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unit) and `systemctl is-active frank-small` on Dankclaw. frank-large
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is not scraped at all — the halogen engine exports no metrics — so
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this alert can only ever name the endpoints that do export one.
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